Re: hide/unhide

[Daniel Pittman]

On Thu, 30 Aug 2001, Jason Thomas wrote:
> anyone farmiliar with this code:
> 
> /* Hide/Unhide CURRENT_PARTITION.  */
> int
> set_partition_hidden_flag (int hidden)
> {
>   char mbr[512];

[...]

>       if (! rawread (current_drive, 0, 0, SECTOR_SIZE, mbr))
>         return 0;

[...]

> I'm trying to figure out why the limitation to four partitions, when
> logical partitions are just as valid, fdisk is able to set the the
> partition type to hidden!

You do know that "Extended Partitions" are implemented by putting a
partition table at the start of a normal partition, because there is a
fixed limit of four partitions in an MS-DOS partition table?

Since this function only reads the table in the Master Boot Record, it
can't modify "Extended" partition tables at all; they are stored
somewhere else.

To support extended partitions, this function would need to modify the
partition table within the partition, not the one in the MBR. That's not
possible with this code, so far as I can see.

I should state that I am not a GRUB developer as such, though, so I may
be failing to know something that makes this work differently from the
way it looks.

    Daniel

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